Authors: Arnaud Cressant Robert U Muller Bruno Poucet
Publish Date: 2002/02/20
Volume: 143, Issue: 4, Pages: 470-479
Abstract
When place cells are recorded from rats running on an elevated Tmaze inside a curtained enclosure that contains distinct experimenter selected stimuli rotations of the maze plus stimuli cause equal rotations of firing fields Here we examined the effects of conflicting rotations of a Tmaze relative to a laboratory frame that contained a large number of fixed stimuli in the environment and asked whether positional firing patterns stayed in register with the maze or the room cues or were modified in some more complex way After maze rotations of 90° 180° or 270° firing fields were stable in the laboratory frame and thus shifted to a different maze arm In contrast rotations of 45° or –45° resulted in dramatic changes of positional firing patterns regardless of their initial position on the maze Crucially even cells whose fields were initially on the central platform underwent major firing pattern alterations although the view of the environment from the platform was unchanged by such rotations Finally we found that altering the visual appearance by removing without rotation one or two maze arms did not alter firing fields on the remaining part of the maze Thus the “remappings” caused by 45° rotations could result from the disturbed relationship between all arms and the room cues or from the changes in the possible paths the animal can take in the environment Taken together our results provide an example of combinatorial coding by the hippocampus in which the place cell representation of the environment was seen to be modified as a unit and not piecewise according to locally available stimuli
Keywords: